JPH0687539B2 - Pre-emphasis control method and apparatus in data transmission system - Google Patents

Description

DETAILED DESCRIPTION [Outline] In a data transmission system, pre-emphasis setting in a training operation between a transmitter and a receiver is performed by a handshake for retraining between a transmitter and a receiver. . This eliminates the need for a large amount of data processing such as extraction of tap coefficients, and simplifies the operating procedure and hardware configuration.

[Industrial application field]

The present invention relates to a pre-emphasis control method and device for a data transmission system.

[Conventional technology]

When data is transmitted from one device (transmission side device) to the other device (reception side device) through the line, the line may function as a filter and the transmission signal may deteriorate the filter. This filter degradation was previously corrected in the modem of the receiving device before,
There is a case where so-called pre-emphasis is performed in which the level of the transmission signal is emphasized in advance in the transmission side device and the signal level becomes flat over a predetermined band when received by the reception side device. As a conventional example of the method for controlling such pre-emphasis, for example, the fourth method is used.
Some are shown in the figure.

In the data transmission system including the transmitter device 1 and the receiver device 2 connected to the transmitter device 1 via the line 3, the pre-emphasis function unit 4 is provided in the modem of the transmitter device 1. The example provided is shown. In the data transmission system having such a configuration, when performing data transmission, first, as a first step operation, a flat signal is sent from the transmission side device 1 to the reception side device 2. On the other hand, in the receiving side device 2, as the second operation, the transmission signal is pulled in by the automatic equalizer. After that, in the receiving side device 2, the third
The tap coefficient of the equalizer is extracted as the operation of the stage. Then, as the operation of the fourth stage, the tap coefficient data is transferred from the reception side device 2 to the transmission side device 1. In the transmission side device 1, as the operation of the fifth stage, the pre-emphasis amount and the like are set based on the transferred data. Then, as the sixth operation, data is transmitted from the transmission side device 1 to the reception side device 2 under steady conditions.

[Problems to be solved by the invention]

However, in such a conventional pre-emphasis control method, an enormous amount of information has to be dealt with in the tap coefficient extraction which is the operation of the third step, and the tap coefficient data which is the operation of the fourth step. In the reverse transfer of, the command information for sending the tap coefficient data must be sent. Further, it is necessary to install a fixed equalizer in the transmission unit in order to set the pre-emphasis amount in the transmission side device 1 which is the operation of the fifth stage. In view of these matters, the conventional pre-emphasis control system has problems that the hardware configuration of the device becomes complicated and the processing operation becomes complicated.

The present invention has been made in view of such conventional problems, and an object thereof is to provide a pre-emphasis control method and apparatus capable of performing initial setting of a fixed equalizer of a transmission / reception unit by a simpler operation procedure. is there.

[Means for solving problems]

In order to achieve the above object, the present invention provides a pre-emphasis function unit in both the transmitter 5 and the receiver 6 of the transmitter / receivers 1 and 2 constituting the data transmission system as shown in FIG. In the training operation between the device 1 and the device 2 on the receiving side, a signal for pre-emphasis (a kind of test signal, corresponding to the flat signal) is sent from the device 1 on the transmitting side onto the line 3 while the device on the receiving side is sent. In step 2, the pre-emphasis signal is determined, and if pre-emphasis is required, a retraining request signal is transferred to the transmission side device 1. As a result, the transmission side device 1 initializes the equalizer.

[Action]

In the training operation, an information area for pre-emphasis is provided in the training signal and sent out on the line 3. On the other hand, the transmission side apparatus 1 has a data holding means such as a register in its transmission section, and stores the pre-emphasis data transmitted on the line 3. When the receiving side device 2 receives the pre-emphasis data and detects the filter deterioration on the line, the receiving side device 2 determines the optimum value and outputs a retraining request signal from the receiving side device 2 to the transmitting side device 1. As a result, the transmission side device 1 determines the optimum value for pre-emphasis, and thereafter performs steady data transmission.

〔Example〕

2 and 3 are views showing an embodiment of the present invention.
FIG. 2 shows an example of the internal configuration of the transmission unit 5 and the reception unit 6 of the modems of the transmission / reception devices 1 and 2. The transmitting unit 5 includes a compromize equalizer 7, which is a means for performing equalization processing for pre-emphasis, and a fixed equalizer 8.
And an equalizer control unit 9 for controlling the compromize equalizer 7 and the fixed equalizer 8, and temporarily storing the pre-emphasis signal data sent to the line 3 when the transceiver operates as the transmitter 1. A register 10 for storing the optimum value data for the re-training handshake during the pre-emphasis operation when operating as the receiving side device 2; The registers 10 and 11 are connected to the line 3 via a signal line 17 for transmission.

The receiving unit 6 is connected to the line 3 via the receiving signal line 18, and a second compromize equalizer 12 that creates optimum value data for pre-emphasis, and a transmitting side device when operating as the receiving side device 2. The third register 13 in which the data for pre-emphasis sent from 1 is received and stored.
And a fourth register for receiving and storing the optimum value data transferred from the receiving side device when operating as the transmitting side device 1.
14, a determination unit 15 that determines whether or not the received pre-emphasis signal data can be used as an optimum value in the system, and a signal that requests retraining is created based on the determination result of the determination unit 15. And a retraining unit 16.

An operation at the time of training in the modem including the transmitting / receiving sections 5 and 6 having such a configuration will be described.

First, when it is desired to send data from the transmitting side device 1 to the receiving side device 2, the transmitting side device 1 creates a data signal including a training signal 21 and a processed data signal 22 as shown in FIG. In the modem according to this embodiment, a data signal storage area 21b for pre-emphasis is provided after the rate sequence storage section 21a which is one element of the training signal 21, and the pre-emphasis data can be set in this storage area 21b. Has become.

At the first stage, the transmitter 5 of the transmitter apparatus 1 sets the compromize equalizer, and pre-emphasis data (PE1) is created here. This data PE1 is a temporary optimum value created by the transmitter 5, and is set in the storage area 21b of the data signal 20 while being stored and held in the first register 10. When the data signal 20 created in this way reaches the receiving unit 6 of the receiving side device 2 which is the partner station, the data for pre-emphasis thereof is taken into the third register 13 of the receiving side device 2. Next, the compromize equalizer 12 of the receiving side device 2 loads the data PE1 and the judging section 15 checks whether or not this is the optimum value in the system. If this is the optimum value, the above training is regarded as successful and no new operation is performed, and the training ends and the processing data transmission operation starts.

On the other hand, when the data loaded from the third register 13 is not the optimum value, the compromise equalizer 12
The optimum value is created by and is transferred to the second register 11 in the transmission unit 5 of the same reception side device 2 through the determination unit 15. On the other hand, a command signal is output from the determination unit 15 to the retraining unit 16, and the retraining unit 16 outputs a signal requesting retraining. This retraining output is sent to the second register 11 through the fixed equalizer 8 and the equalizer control unit 9 in the transmission unit 5, sent out on the line 3 and sent to the transmission side device 1. As a result, a retraining shake hand operation is performed between the transmission side device 1 and the reception side device 2. At this time, the optimum value data stored in the second register 11 is transmitted by the transmitting device 1 by the shake hand operation.
Is input to the fourth register 14 of. Then, the optimum value data once stored in the fourth register 14 is transferred to the equalizer control unit 9 in the transmission unit 5 of the transmission side apparatus 1 and further input to the compromize equalizer 7. Then, the pre-emphasis optimum value data is written in the first register 10 by the compromize equalizer 7, and the first register 10 in which the data PE1 is stored at the first stage is updated by the optimum value data and is equalized. The initial setting of is performed.

As described above, since the pre-emphasis handshake is performed by the retraining operation, it is not necessary to particularly insert the pre-emphasis processing sequence during the initial operation of data transmission, and it is not necessary to extract a large number of tap coefficients. The bits required for data processing due to the provision of the compromize equalizer 7 are 7 bits in the pre-emphasis reception cycle, 4 bits for the compromize equalizer setting information of the local station transmitter 5, and the partner station transmitter 5
4 for Compromise equalizer setting request information
A total of 16 bits, 1 bit for indicating whether or not to perform pre-emphasis, is sufficient.

〔The invention's effect〕

As described above, according to the present invention, the receiving side device determines whether or not the pre-emphasis data sent from the transmitting side device is the optimum value, and the optimum value is created by the retraining handshake. Since the setting is performed, the training process can be simplified and the hardware configuration can be simplified.

[Brief description of drawings]

FIG. 1 is a diagram showing the principle of the present invention, FIG. 2 is a block diagram showing the configuration of a transmitting / receiving section of a modem to which the present invention is applied, and FIG. 3 is a diagram showing the configuration of a data signal created when the present invention is implemented. FIG. 4 and FIG. 4 are schematic configuration diagrams of a data transmission system adopting a conventional pre-emphasis control. 1 ... Transmission side device 2 ... Reception side device 3 ... Line 4 ... Pre-emphasis function part 5 ... Transmission part 6 ... Reception part 7, 12 ... Compromise equalizer 8 ... Fixed equalizer 9 ... Equalizer control part 10 ... First Register 11 ... second register 13 ... third register 14 ... fourth register 15 ... judging section 16 ... retraining section

Claims (2)

[Claims] 1. In a training operation between a transmission side device (1) and a reception side device (2) of a data transmission system, while transmitting pre-emphasis data from the transmission side device to the reception side device, Retaining the data in the transmission side device, determining whether the pre-emphasis data in the reception side device is the optimum value in the system, and if the determination result is not the optimum value, retraining request A step of sending a signal from the receiving side device to the transmitting side device, and transmitting the optimum value in the system by a retraining handshake, and in the transmitting side device receiving the optimum value, transmitting based on the optimum value Pre-emphasis in the data transmission system, which comprises the steps of updating the pre-emphasis data held in the unit and initializing the equalizer. Control method. 2. A transmitting / receiving device (1), (2) for data transmission.
The equalizer (7) provided in the transmitting section (5) for creating pre-emphasis data, the first register (10) for temporarily storing the pre-emphasis data, and the transmitting / receiving apparatus Second register (11) for temporarily storing the optimum pre-emphasis value created by the device itself when receiving
And an equalizer control unit (9) for controlling the compromise equalizer and a pre-emphasis data received from a transmission side device, which is provided in a reception unit (6) of a transmission / reception device for data transmission. A third register (13), a judgment section (15) for judging whether or not the pre-emphasis data here is an optimum value in the system, and a pre-emphasis optimum based on the judgment result of the judgment section (15). Compromise equalizer (12) that creates a value, retraining unit (16) that makes a retraining request to the transmission side device based on the determination result of the determination unit (15), and transmission operation of the transmission and reception device And a fourth register (14) for temporarily storing the pre-emphasis optimum value received from the receiving side device, the equalizer control section (9) of the transmitting section is A pre-emphasis control device in a data transmission system, characterized in that the pre-emphasis data is updated by controlling the compromize equalizer (12) based on the optimum pre-emphasis value temporarily stored in the fourth register (14). .